The present invention refers to a cage for a tapered roller bearing.
A pocket cage of a bearing has axially opposite side rings, and axially extending, circumferentially spaced apart arms joining the rings. Cages for tapered roller bearings of this type having two annular, axially opposite end side rings, which side rings are of different diameter and do not intersect axially, are known, for instance, from U.S. Pat. No. 4,288,129. The pocket openings in these cages are bordered by arms having surfaces intended to separate and space the rollers and prevent their skewing excessively. The pockets are formed using axially moved pushers. In U.S. Pat. No. 4,288,129, the pusher lying radially inside the mold parting line of the cage is pulled out in the axial direction which is away from the small side ring and toward the larger side ring. Radially inside the mold parting line, the pocket surfaces in the arms of the cage, which surfaces are produced by the pusher being pulled out, can be completely adapted to the profile of the roller due to the widening profile of the roller in that axial direction. But, this shaping of the pocket surfaces is not possible in that region of the cage that lies radially outside of the mold parting line because the second pusher which is extractable, here in the axially opposite direction from the first pusher, makes necessary the provision of pocket surfaces which are spaced from the roller outer surfaces and the position of which is determined by the largest roller diameter. For the sake of simplicity, these pocket surfaces, arranged in each case on one arm of the cage, are parallel to each other. In the pocket regions lying radially outside the mold parting line, no pocket sections which engage behind the rollers are able to be present. In the case of certain size relationships, this can lead to cages which, in the region of the large side ring of the cage, have only relatively short axial length sections which grip the rollers. Of course, they are still gripped near the small side ring. However, this can still lead to the rollers no longer being gripped sufficiently and, in particular, to the rollers falling out of the cage upon assembly of the bearing. Although these roller gripping sections near the small side ring can be lengthened by locating the mold parting line radially further toward the outside, since the location of the parting line also determines the location of the inside of the large side ring, in that case the large side ring will be so weakened in its cross section that the stability of the cage will be considerably reduced.